Table 1 Symptoms and therapy (a), imaging findings (b), laboratory findings (c) and CSF characteristics (d)

a) Symptoms and therapy

Respiratory symptoms

day 1 – day 8

Anosmia and ageusia

day 4 – day 15

Onset of ataxia

day 16

Scale for the assessment and rating of ataxia (SARA)

•day 16

14 points

•day 35

5 points

•day 119

1 point

Therapy with acyclovir 3 × 840 mg/d iv

day 29 – day 34

Therapy with methylprednisolone 500 mg/d iv

day 29 – day 33

b) Imaging

 Brain-MRI

Slight generalized brain atrophy with accentuation of atrophy in the cerebellum

 FDG-PET

No signs of metabolically active malignancies, no cerebellar hyper- or hypometabolism

 Chest X-Ray and -CT scan

Bipulmonary opacities accentuated in both upper lobes (inflammatory infiltrates)

c) Laboratory findings

Result

Normal range

Nasopharyngeal swab for SARS-CoV-2 RNA

positive on day 18

negative

negative on day 22

Creatin kinase (U/L)

38

<  190

Leukocyte count (10⁹/L)

7.84

3.0–9.6

Thrombocyte count (10⁹/L)

595 10⁹/L

143–400

Hemoglobin (g/L)

150

134–170

C-reactive protein (mg/L)

3.9

< 5

Anti-neuronal antibodies*

negative

negative

d) CSF characteristics

Day 23

Day 33

CSF Cell Number (/ul)

< 1

4

≤4

CSF Lactate (mmol/L)

1.5

2.3

1.7–2.6

Glucose Ratio (CSF/Serum)

0.7

0.6

> 0.5

Albumin Ratio (CSF/Serum)

6.4 × 10³

<  8.1 × 10³

Virus PCRs in CSF**

negative

not done

negative

Metagenomic virus sequencing

not done

negative

negative

Oligoclonal bands (OCB)***

type 4 (identical OCB in CSF and serum)

type 4 (identical OCB in CSF and serum)

type 1 (no OCB in serum and CSF)

Intrathecal synthesis of IgG (i.e. CSF/serum antibody index) reactive against

•SARS-CoV-2 NP****

inconclusive

0.64

<  1.5

•SARS-CoV-2 S1

inconclusive

0.99

•SARS-CoV-2 S2

inconclusive

0.19

•Herpes simplex virus type 1/2

inconclusive

negative

<  1.5

•Varicella zoster virus

inconclusive

1.01

<  1.5

•Borrelia burgdorferi

negative

not done

<  1.5